Liquid spray apparatus and system

ABSTRACT

A liquid spray head ( 10 ) e.g. to spray liquid for dust control or watering. The spray head has a body ( 11 ), an inlet ( 12 ) for receiving the liquid to be sprayed, a spray outlet, and at least one adjuster ( 15,16,17,18 ) arranged to adjust size and/or position of the outlet aperture such that a width or position of the aperture is variable, or both the width and position of the aperture are variable, relative to the body, to thereby deliver a desired rate, pattern or direction of liquid spray through the aperture. The adjuster can be ram ( 17,18 ) actuated controlling two coaxially aligned collar assemblies ( 15,16 ) with left and right adjusting leaves ( 25,26 ). A depth actuator works an outer body cover ( 24 ) to adjust vertical height of the outlet aperture. Spray aperture size and/or direction can be controlled based on vehicle speed and desired spray pattern/direction.

FIELD OF THE INVENTION

The present invention relates to a liquid spray apparatus and system, such as for use in dust suppression from vehicles.

BACKGROUND TO THE INVENTION

There are many applications for liquid spray apparatus and systems, such as for fire fighting both from vehicles and in static installations, for agriculture in irrigating/watering crops or grass, and in dust suppression at industrial sites, such as road building, landfill sites and mine sites.

The following description will focus on applications for dust suppression. However, one or more forms of the present invention may be used wherever control of liquid delivery by spraying is required.

Large open area sites where the underlying soil is disturbed often require some form of dust suppression. This is conducted for environmental reasons, chiefly to prevent movement of windblown (potentially contaminated) soil from one area to another, but also to prevent soil blowing as dust into urban, commercial or traffic areas. Governmental and environmental concerns for public health and safety have increased consciousness for the need to control dust emanating from such sites and operations. Controlling dust created by vehicle movements helps to improve workers conditions, improve local community acceptance of the presence of the site and operations carried out, and increased productivity because vehicles and their operators are able to travel faster and more safely due to improved vision of the immediate roadway edges and surface as well as a clear road ahead.

Mine sites, road/building construction sites and landfill sites are typical examples of where such dust suppression is needed. Dust is typically created where excavators have moved or removed the topsoil covering and the underlying soil has dried out. On mine sites, for example, roadways are created inclining down into the mine. These roadways are used to gain access into the mine and by the dump trucks (aka haul packs) to remove the mined material out of the mine. Constant use creates dust on the roadway surface which needs to be damped down. A water tanker/water cart or adapted dump truck carrying a reservoir of water are generally used to spray the water over the ground surfaced to damp down the dust. The simplest form of spraying uses a spray bar or series of spray heads across one end of the vehicle to deliver a spray of water as the vehicle traverses forward/backward. However, other than an on-off control of the water spray, no other control was used. Consequently, regardless of the speed of the vehicle the sprays would deliver water at a near constant rate (subject to water pressure from the ever reducing onboard reservoir).

More recent developments have introduced speed controlled spraying. The amount of water delivered when spraying is related to the speed of the vehicle. An example of such a system is disclosed in international patent application PCT/US98/02601 published as WO 98/35104. An electrostatic water spray dust suppression system for use with vehicles is disclosed. A control system monitors movement of the vehicle, and activates or deactivates the sprayer(s) dependent upon movement and speed of the vehicle. Such a system relies on creating a fog of electrostatically charged water droplets that, due to their electrostatic charge, are mutually attracted to dust particulates in the air. The water droplets and dust particulates agglomerate and fall to the ground. However, very fine spray head apertures are required to create the fine fog or mist spray. Also, an electrostatically charged tip is required to transfer charge to the water droplets as they are sprayed. The fine spray apertures can easily become clogged in the very dusty environment or due to hard water causing calcification over time, or because the water may not be sufficiently filtered before being sprayed. Furthermore, fine fog/mist spraying produces very light droplets that can tend to be blown by the wind away from the area to be damped before having any significant effect, resulting in water being wasted.

The aforementioned spraying equipment and techniques does not provide for adjustment of the spray pattern or direction. The vehicle travels forward/backward over the area to be damped and simply sprays outward/downward in a linear pattern using fixed spray heads in the direction the vehicle is traveling, whether or not the spraying is speed controlled.

There is also a need to conserve and not waste water. Water spraying related to vehicle speed helps to reduce water wastage by reducing over watering of road areas when the vehicle is travelling slowly or under-watering when the vehicle is travelling faster. Over-watering can occur when a water cart or truck is travelling up an incline and engine revs (and therefore the water pump output) are high. This can result in washing away of the road surface.

To apply sufficient water across the width of an industrial site roadway, often up to 25 m wide or more, it is necessary to use multiple spray heads. Typically three spray heads will be used simultaneously across the width of a spray bar on the vehicle—one in the centre and one each towards the left and right ends of the spray bar. Such a configuration creates some overlap between the centre and each of the left and right end spray patterns. This results in more water applied in the centre of the roadway than at the edges. The overlap areas can cause the roadway to wear or wash away over time, causing potholes or gullies in the roadway.

The spray pattern and amount of water delivered can be adjusted by setting each of multiple spray heads. The width and depth of the spray aperture of each spray head across a spray bar of a vehicle can be manually adjusted and set. However, correct adjustment is difficult to obtain and retain. Variations in water pressure also vary the spray pattern, and consequently, some overlap or non-sprayed area will occur.

It has been realized that a single spray head able to cover the full desired width of spray is desirable.

With the aforementioned in mind, it is desirable for the present invention to provide an adjustable spray head for spray delivery of a liquid to an area, the spray head having an adjustable width and direction of spray.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of admission that the prior art forms part of the common general knowledge in Australia.

SUMMARY OF THE INVENTION

With the aforementioned in view, an aspect of the present invention provides a liquid spray head configured, in use, to deliver a spray of liquid for dust control, the spray head including a body, an inlet for receiving the liquid to be sprayed, an outlet for delivery of the liquid for spraying, at least one adjuster arranged to adjust size and/or position the outlet such that a width or position of the outlet is variable or both the width and position of the outlet are variable, relative to the body, to thereby deliver a desired rate, pattern or direction of liquid spray.

Thus, advantageously, the rate, width and/or direction of spray may be controlled for a single spray head a single spray head with variable width and variable control of volume or rate of liquid delivery. Thus, not only may the width and/or position of the outlet be controlled, but also the pressure, and therefore rate of flow through the spray head may be controlled.

The adjuster may be mechanically actuated, such as by one or more rams (which may be hydraulically or pneumatically operated) or by one or more electrically driven solenoids. Thus, remote operation of the spray head can be effected, such as from a cabin of a vehicle or other remote location, such as a control centre, for a remotely operated vehicle.

The spray head may include coaxial leafs (inner and outer leafs) within or connected to the body. The leaves define the outlet between a respective edge of each leaf, and the leafs may be rotated relative to one another about the common axis. Thus, the size of the outlet may be controlled between a minimum aperture to a maximum aperture. Minimum aperture may be a fully closed aperture. Also, position of the outlet may be varied by relative rotation of the leaves such that the leaf edges defining the outlet is effectively rotated relative to the body. It will therefore be appreciated that the spray pattern and direction may be varied by adjusting the angular width and/or position of the outlet.

It will therefore be understood that three adjustments may be made:

Left and right side angular adjustment to control the width and position of the outlet, and thirdly the outlet depth (spray head depth).

Left and right adjustment may be up to around 90 degrees left and up to around 90 degrees right from a centreline, such as a centreline of the vehicle or roadway i.e. 180 degrees coverage side to side in total.

The spray head may be adjusted in conjunction with vehicle road speed or engine/pump speed. For example, the spray head outlet and pump speed may be controlled by a vehicle speed signal, such as from a processor.

It may be possible to replace the processor with a signal from a vehicle information management system. Such a system can provide a greater integration for the spray head and system, and therefore be more familiar to maintenance personnel having particular knowledge of the vehicle carrying the reservoir of liquid to be sprayed.

The liquid may be water, but may alternatively be water containing dust suppression chemicals, or may be a foam type liquid, which may be water based foam. Chemical(s) may be introduced to the water as it is sprayed, such as by eduction, or may be contained with the water prior to spraying.

A multi-stage water pump drive may be used. For example, a three stage drive hydro-motor may be used to adjust pump speed in three steps. Thus, the pump may be maintained within a speed range and therefore within a desired liquid delivery pressure range. Switching between pump drive stages may be effected by mechanical or electrical operation. For example, a solenoid controller may be used to selectively actuate pump speed stages.

Liquid delivery pressure may be controlled by providing a pressure relief system enabling return of liquid back to the onboard supply reservoir.

A processor, controller or vehicle information management system may utilise vehicle engine speed to adjust the pump drive stages in operation, thereby maintaining water pressure and water pump speed within a desired range. The processor, controller or vehicle information management system may use a signal relating to a vehicle speedometer signal as a factor influencing adjustment of the spray head outlet, such as relating to vehicle ground speed.

In use, the spray head outlet is adjusted by the vehicle operator dependent upon a desired spray pattern, direction and/or rate of delivery. Operator controls, such as in a cabin or external control panel of the vehicle provide for left and right spray width adjustment. The operator therefore determines left and right angular extent of the spray pattern.

Spraying may be controlled by an actuation means, such as a switch or foot pedal in the vehicle. The actuation means may be ON from a vehicle standing start. As vehicle speed increases, say past 5.0 km/h, spraying comes into operation. As vehicle speed increases, the spray head outlet volume control may come into operation, thereby permitting a greater liquid flow rate through the outlet to match increased vehicle speed. The faster the vehicle travels the more liquid needs to be put through the spray head. Thus, vehicle speed and liquid spray volume can be matched proportionally.

The pump drive may be switched off and supply of liquid to the spray head may be isolated, such as by using an isolation valve and/or liquid return system, when liquid spraying is not required or the vehicle speed is below a selected speed, say 5.0 km/h,

The spray head may be used for pulse spraying the liquid. Pulse spraying is a technique used on ramps and inclines of roadways. Spraying is turned on and the road surface is wetted for a certain distance, then spraying is interrupted and the road surface left dry for a certain distance. Typically, 50 meters wet 50 meters dry, though other distances of wet-dry are envisaged. Pulse spraying provides a safety feature. A vehicle, such as a dump truck, travelling down a ramp fully loaded may skid under braking on the wet area is able to regain control in the dry area. At least one embodiment of the present invention provides for liquid spraying control via a controller which utilizes pulse spraying by controlling opening and closing the outlet aperture of the spray head. The outlet aperture may be gradually opened and closed, such as in a sinusoidal wave form control, rather than a just on-off-on of known pulse spraying. Pulse spraying control may be effected using the controllability and variability of the spray head actuator(s) rather than a simple onboard isolating valve shutting off supply from the pump. This would have the effect of making the whole road surface wet but the volume of liquid in some areas is only light thereby still aiding dust control but also allowing vehicles to maintain contact under braking when traveling down an incline or prevent wheelspin on an incline.

The spray head may be used as part of a water cannon or hose reel supply system. Alternatively, the spray head may be connected to a fixed installation where variable angular liquid delivery, direction and/or volume are required, which may be effected remotely or manually by adjustment of the spray head adjuster.

The spray head may form part of a liquid spray system, including a reservoir of a liquid to be sprayed, a pump and connecting conduit to deliver the liquid from the reservoir at pressure to the spray head, pump control means to control pump speed, and spray head adjustment control means to control the outlet of the spray head to effect a desired angular spray width, and preferably spray direction and spray volume.

The spray head may include a hydraulic actuator, such as a cylinder or ram, operatively connected to the cam of the rotary actuator. Connection may be by linkage, such as a lever. The hydraulic actuator may be fitted with a resilient return means, such as a coil spring. Thus, once the hydraulic actuator is extended, the resilient return means returns the cam, and thus the cam operated vertical movement of the spray head opening, to a closed position or partially open/closed position. A hydraulic control valve may be fitted that provides a variable pressure to this actuator. In use, the hydraulic actuator extends and retracts against the spring force according to the increase or decrease in hydraulic pressure it receives. The hydraulic control valve may communicate with a PLC, which preferably takes a road speed input and converts it into a signal to control the hydraulic pressure to the cylinder. Thus, as the vehicle moves faster the cylinder extends and provides the mechanical force to operate the variable mouth width of the spray pattern.

One or more embodiments of the present invention may include a control system to control actuation of the spray head. Such control systems may employ hydraulics and meter the spray mouth aperture by controlling hydraulic pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a spray head in perspective according to an embodiment of the present invention.

FIGS. 2A to 2C show respective top, front and side views of a spray head according to an embodiment of the present invention.

FIGS. 3 a and 3 b show respective right side and left side perspectives of a spray head showing spray width adjustment means according to an embodiment of the present invention.

FIG. 4 shows a cutaway section through the embodiment of the spray head shown in FIGS. 3 a and 3 b.

FIG. 5 shows a right side view of a spray head with rotary actuator according to an embodiment of the present invention.

FIGS. 6 to 9 show control of spray patterns to the left and right sides from a spray head by adjusting spray aperture width and position according to the embodiment shown in FIG. 5.

FIGS. 10 and 11 show control of spray rate by adjusting aperture opening height of the spray head according to the embodiment shown in FIGS. 5 to 9.

FIGS. 12 to 16 show an embodiment of the present invention including a hydraulic actuator arranged to operate a cam device to effect vertical opening of the spray opening. FIG. 12 is a perspective view, FIG. 13 a rear view, FIG. 14 a vertical cross section, FIG. 15 is a side view and FIG. 16 a front view.

FIGS. 17 to 19 show perspective views with alternative spray patterns from the opening of the spray head according to embodiments of the present invention. With spray directed outwards from the spray head, FIG. 17 shows a spray pattern arc to the left, FIG. 18 shows a spray pattern arc to the right, and FIG. 19 shows a spray pattern covering both left and right.

FIGS. 20 to 22 show top down (plan) views of a spray head according to an embodiment of the present invention. With spray directed outwards from the spray head, FIG. 20 shows a spray pattern arc to the right, FIG. 21 shows a spray pattern arc to the left, and FIG. 22 shows a spray pattern arc covering both left and right.

FIGS. 23 to 26 show adjustment of the vertical opening height of the spray aperture dependent upon road speed. The spray aperture opens further with increasing road speed to ensure sufficient wetting coverage of the road.

FIGS. 27 and 28 show side sectional views of a spray head according to an embodiment of the present invention.

FIGS. 29 and 30 show perspective sectional views of a spray head according to an embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENT

The invention will now be described with reference to the accompanying figures.

FIG. 1 shows an embodiment of the spray head 10. The spray head has a main body 11 with an inlet 12. The inlet has a flange 13 with a number of apertures 14 for mounting the spray head to a spray bar or conduit of a vehicle or to another mobile or fixed installation. The spray head has a two coaxially aligned collar assemblies 15,16. The inner collar assembly 15 is actuated by the left hand actuator ram 17. The outer collar assembly is actuated by the right hand actuator ram 18 (see FIGS. 3 a, 3 b and 4). The left and right hand actuator rams are mounted to an actuator mount 19 which also supports the spray head body. Each of the actuator rams is provided with a position feedback means, such as proximity sensors, arranged to convey a signal relating to an actuation extent of the respective ram. Ram extension position detection may be continuous or just certain position steps may be detected. Alternatively, rotary position i.e. angular movement, of the inner and outer collars may be detected, which are related to the extent of retraction or extension of the respective rams.

Each ram is pivotably connected to the respective collar assembly via a pivot 20,21 and pivot bracket 22,23.

A spray head body cover assembly 24 covers the lower extent of the inner and outer collar assemblies and the spray head depth (aperture depth/height) adjuster. This cover assembly also provides the outlet aperture adjusting sleeve 36. This outlet aperture sleeve is moved up or down relative to the left and right width adjusting leaves 25,26. A depth actuator situated inside the cover 24 pushes against or pulls towards a plate 34, thereby acting on the supports 38 on the base 40 of the cover 34. This action causes the side wall 42 of the sleeve 36 to move up and down as needed, thereby varying the upright depth of the outlet aperture 25 by vertically reducing or increasing the outlet aperture 25 opening.

FIGS. 2 a to 2 c show the spray head in top, front and side view. The front view, FIG. 2 b, shows the outlet 25 closed. The converging or overlapping edges of the inner and outer collar assembly leaves 26,27 shut the outlet aperture. When actuated, the rams rotate the respective collar leaf and open the outlet aperture to a desired amount. Also, the left-right orientation of the outlet aperture can be controlled. For example, if desired, the right hand ram can be retracted and the left hand ram extended but a lesser amount than the right hand ram is retracted, to rotate the outlet aperture to the right. The opposite can be done to rotate the outlet aperture to the left. The outlet aperture width and position can be varied by controlling the extent to which one collar leaf rotates compared to the other and in which direction.

FIGS. 3 a and 3 b show right and left perspectives of the spray head 10 with actuator rams 17, 18. The left hand ram 17 is shown retracted and the right hand ram extended. The leaf 26 of the right hand collar assembly 15 is therefore rotated to the left. The leaf 27 of the left hand collar assembly 16 is also shown rotated to the left. A gap is formed between the respective edges 28,29 thereby defining the outlet aperture 27, rotated to the left side of the spray head 10.

The angular position and width of the outlet aperture 27 can be varied depending on the extent of rotation of each leaf 25,26 and in which direction they are each rotated.

FIG. 4 shows a cutaway section through the spray head 10. The outlet aperture depth actuator is shown generally at 30, which is normally housed within the cover 24. The linear actuator 32 of the depth actuator 30 controls the position of the sleeve 36 formed by the cylindrical wall of the cover relative to the inner and outer collar assemblies. This varies the length of the outlet aperture 25 while the leaves 26,27 of the inner and outer collar assemblies rotate transversely to vary the width of that outlet aperture.

In use, the spray head can be installed as part of a liquid spraying system. Typically the spray head might be used mounted to a vehicle in a water spraying system for use in damping down roadways. However, other applications are deemed to fall within the compass of the present invention. For example, in fire fighting applications or oil hydrocarbon dispersal applications. A pump delivers the liquid to the spray head from a supply reservoir. This reservoir may be carried by a vehicle to which the spray head is mounted or by a separate vehicle, such as a water tanker. Because of the adjustability of the outlet aperture of the spray head, only a single spray head is needed to cover a full width of a typical roadway. The width of the spray head outlet aperture can be increased or decreased by the adjuster. This allows the angular spray pattern to be adjusted. Also, the bias towards the left side, straight-ahead or right side can be adjusted by moving the outlet aperture towards the left, straight or right as required. Furthermore, optionally the depth/height of the outlet aperture can be adjusted to increase flow rate through the aperture. Thus, with variable control of width and height/depth of the outlet aperture, and direction, one single spray ahead can be used to provide a required spray pattern or amount of liquid. Adjustment can be linked to cabin controls, and optionally to a variable speed pump. Flow rate can be linked to vehicle speed so that the amount of liquid being sprayed is matched to vehicle speed and road conditions. A higher flow rate can be used where the vehicle is moving faster. Flow rate can be controlled to match vehicle speed even if engine speed is high, such as when negotiating a steep incline. A variable stage pump drive may be employed so that pump speed is matched to delivery requirements. If a high volume flow rate is required with the vehicle static, such as in a fire fighting role, the vehicle can be parked, the pump driven at high speed via the multi stage pump drive and the engine driving the pump set at high revs.

Varying the width of the outlet aperture can be achieved by varying the separation between edges of sections of coaxially aligned sleeves. Rotary movement of one sleeve relative to the other causes a change in the width of the aperture and therefore a change in spray pattern. Flow rate can be varied by adjusting the height of the outlet aperture as well as pump speed. A rotary or linear actuator may be employed to control the height of the aperture.

FIGS. 6 to 11 show an embodiment of the present invention with rotary actuated spray aperture opening height variation. The spray head 60 has linear actuating rams 62,64 to adjust position and width of the spray aperture to control the sideways angle of spray and direction. One ram moves a first curved member 66 and the other ram moves a second curved member 68. These gap between edges of these curved members defines the sideways extent of the spray aperture between closed, open towards one side, open towards the other side, and open towards both sides. This defines the sideways spray pattern, as shown in FIGS. 6 to 9. Reference item 70 shows a right side spray pattern (approximately 90° right). Reference item 72 shows a left side spray pattern (approximately 90 left). Reference item 74 shows left and right side spray pattern (approximately 180° left to right). These spray patterns are directed in front of or behind a vehicle depending on the positioning of the spray head. A vehicle may be fitted with front and rear spray heads and so spraying can be done in of and behind a vehicle.

A rotary actuator 76 includes an actuator cam 78. Eccentricity of the cam causes the lower casing 80 to move up or down depending on the direction of rotation of the cam. This movement varies the vertical opening height of the spray aperture 82. The cam is rotary actuated by an actuator mechanism 84 connected by a linkage 86 between a first actuator mechanism arm 88 and a cam actuator arm 90. rotation of the cam causes the cylindrical casing 80 to move up or down depending on the direction of cam rotation. This varies the opening height of the aperture created between the edges of the curved members 66,68. Thus, selected positions of the curved members and the outer casing determine spray direction, spray angle and spray rate (volume and/or distance of spray). Spray pressure may also be controlled by a valve prior to the liquid entering the spray head or within the spray head. Reference item 92 shows movement direction arrows relating to control of the aperture opening and thus the spray pattern 94.

FIG. 7 shows the curved members closed together to shut off the sideways spray pattern.

Complete closure of the spray head aperture may be effected by moving together the edges of the curved members and/or moving the outer casing upwards, or both.

FIG. 10 shows initial opening of the aperture by operating the rotary actuator and thereby moving the outer casing downwards, and FIG. 11 shows the rotary actuator moved further and the aperture more fully open, as in FIG. 5.

FIGS. 12 to 16 show various views of a spray head according to an embodiment of the present invention with a hydraulic ram 100 actuated cam actuator 78 for increasing and decreasing the vertical height of the spray head spray opening 82 and thereby opening and closing the size of the opening to vary volume and spray pressure. The ram includes a cylinder 102 and piston 104. The lower end 106 of the piston is connected to a pivot 108 attached to a linkage 110 connecting to the cam actuator 90 and thereby to the cam 78. It will be appreciated that the ram may be reversed with the cylinder connected to the pivot 108 and an upper end of the piston connected to an upper mount 112 (as shown in the cutaway view in FIG. 12). The upper extent 114 of the hydraulic ram 100 is covered by a protective cover 116. The ram may be single acting with a resilient means return actuator or may be double acting with hydraulic pressure retracting the ram. A double acting ram may be provided where finer control over ram extension and retraction is required. In use, the ram extends which causes the linkage to rotate the cam. This action causes the lower casing 80 to raise or lower depending on the direction of extension/retraction of the ram and direction of rotation of the cam.

In the cutaway FIG. 14, one ram 18 is shown for actuating a curved member (or leaf) 26. The second ram 17,62 is arranged to move the opposite second curved member 27. Thus, the horizontal size and position of the spray opening can be varied by control of the extent of each ram 17,18. The cutaway view in FIG. 14 also shows the lower ends 118,120 of the respective curved members 26,27 connected to a support member 122. Movement of the cam actuator 78 connected to the support member 122 causes the outer casing 80 to move up or down as required in order to open/close the vertical spray opening height and thereby control spray pressure and/or volume. Resilient means, such as a return spring may be housed within the actuator ram 100, externally of that ram around the cylinder 102 and/or externally elsewhere, such as connected between the lower mount pivot 108 and another portion of the spray head device or vehicle framing. A benefit of using at least one hydraulic ram to actuate the cam actuator is that higher torque can be applied compared with an electrical actuator. Also, hydraulic systems of the vehicle can be utilized as the pressure source for the hydraulic actuator.

FIGS. 17 to 19 show the spray head 10 with the left (L) and right (R) side hydraulic actuators 17,18 actuated to direct a water spray pattern as required. For example, FIG. 17 shows the left side hydraulic actuator 17 retracted and the right side hydraulic actuator 18 extended. This causes the respective left hand leaf 25 to rotate to the left L, and the right hand leaf 26 to rotate to the left L. FIG. 18 shows the left hand actuator ram 17 extended and the right hand actuator ram retracted, thus moving the aperture to the right R. The amount each respective leaf 25,26 rotates governs the transverse (lateral) opening width of the aperture as well as the left to right position of the aperture. As shown in FIG. 19, retracting both of the left and right hand rams 17,18 causes the spray aperture to open wider, thereby allowing a higher volume of water to be sprayed, covering both left and right sides and forward (i.e. rearward in respect of a vehicle fitted with the spray head and spray equipment).

FIGS. 20 to 22 show top views (plan views) of the spray head with spray patterns as shown in corresponding FIGS. 17 to 19.

FIGS. 23 to 26 show the variance in aperture vertical height opening dependent upon road speed. As the vehicle moves forward and increases speed, a speed sensor (not shown) signals a controller (not shown) which controls actuation of the actuator 100 operating the outlet aperture adjustment sleeve 36. As speed increases, the controller prides proportional control to the actuator 100 via a hydraulic pump to open the aperture vertically. This controls rate of water delivery from the spray head. As the vehicle slows down, the rate of water spray can similarly be reduced automatically based on the same speed sensing control. A vehicle operator may also have a manual override to manually control the amount of water sprayed at a given location or time. This can be useful where overspray is required above a rate delivered at a given speed, or when the vehicle is stationary or traveling below a speed at which water is sprayed automatically.

FIGS. 27 and 28 show side sectional views through a spray head 10 according to an embodiment of the present invention. The embodiment shown in FIG. 28 is the same as that shown in FIG. 14 and reference numerals are the same between the two. FIG. 27 shows the same embodiment as FIGS. 14 and 28. In FIG. 27, the actuator ram 100 is shown extended, which has operated the linkage 110 and cam mechanism 78, which caused the outer casing 80 to move downward and open the outlet aperture 82. Use of the left actuator ram 17 (not shown) and right actuator ram 18 varies the transverse position and opening width of the spray aperture 82. Use of the upright hydraulic ram 100 varies the vertical height of the aperture. Thus, spray volume control can be achieved by varying the vertical size of the aperture and left/right/straight spray pattern can be varied by use of the left and right rams.

A filter can be provided in the supply to the spray head. This may be a coarse filter to remove larger debris from the water (such as rocks, sticks etc). A finer filter can be provided as required. A filter can help prevent the aperture becoming blocked with debris or the opening/closing mechanism becoming jammed. Spray volume may be varied by controlling pump speed or varying the pump capacity i.e. by changing the pump for a larger/smaller pump or adding one or more additional pumps.

FIGS. 29 and 30 show perspective sectional views through a spray head according to an embodiment of the present invention. In this embodiment, the right hand side actuator ram 18 is shown retracted in FIG. 29 and extended in FIG. 30. As shown most clearly in FIG. 30, this causes the right hand or inner leaf 26 to rotate. Likewise, the left hand actuator ram 17 can move the left hand or outer leaf 27. 

1. A liquid spray head configured, in use, to deliver a spray of liquid for dust control, the spray head including a body, an inlet for receiving the liquid to be sprayed, an outlet for delivery of the liquid for spraying, at least one adjuster arranged to adjust size and/or position of an aperture of the outlet such that a width or position of the aperture is variable, or both the width and position of the aperture are variable, relative to the body, to thereby deliver a desired rate, pattern or direction of liquid spray through the aperture.
 2. A spray head according to claim 1, wherein the adjuster is remotely mechanically or electrically actuated.
 3. A spray head according to claim 2, wherein the adjuster includes one or more hydraulically or pneumatically operated actuators or one or more electrically driven solenoids to vary the width and/or position of the aperture.
 4. A spray head according to claim 3, wherein the one or more hydraulic or pneumatic actuators are rams.
 5. A spray head according to claim 1, including leaves defining an aperture of the outlet between a respective edge of each said leaf.
 6. A spray head according to claim 5, wherein the leaves include two leaves, one leaf forming part of an outer collar assembly and the other leaf forming part of an inner collar assembly, the inner and outer collar assemblies being coaxial.
 7. A spray head according to claim 5 or 6, wherein the leaves are curved and mounted for rotation relative to one another about a common axis.
 8. A spray head according to claim 5, the adjuster configured to move one or more said leaves left or right to provide an outlet aperture rotational range of up to 90 degrees left to 90 degrees right from a centerline.
 9. A spray head according to claim 1, the adjuster being actuated in conjunction with vehicle road speed or engine/pump speed.
 10. A spray head according to claim 9, wherein size of the spray head outlet aperture and pump speed are controlled dependent upon a signal related to vehicle speed or engine speed.
 11. A spray head according to claim 1, the at least one adjuster including a rotary actuated spray rate adjuster that increases the spray aperture for greater spray rate and reduces the spray aperture for reduced spray rate.
 12. A spray head according to claim 11, wherein the spray rate adjuster includes a cam mechanism whereby rotation of the cam in one direction effects movement of a member to reduce the aperture in height, and rotation in another direction effects movement of the member to increase the aperture in height, thereby controlling spray rate by controlling volume of liquid per period.
 13. A spray head according to claim 1, wherein adjustment of the spray head is integrated with and controlled in conjunction with vehicle control systems.
 14. A spray head according to claim 1, further including a hydraulic actuator arranged to operate a cam actuator to vertically increase or decrease the aperture of the spray head outlet.
 15. A spray head according to claim 14, wherein the hydraulic actuator includes a hydraulic ram.
 16. A spray head according to claim 14, further including at least one resilient return means acting on the hydraulic actuator to decrease opening of the aperture of the outlet.
 17. A liquid spray system including a spray head according to claim 1, a liquid supply reservoir, a pump to deliver liquid from the supply reservoir to the spray head, a conduit connecting the reservoir to the pump, and a conduit connecting the spray head to the pump.
 18. A liquid spray system according to claim 17, wherein the system is mounted to a vehicle.
 19. A liquid spray system according to claim 18, wherein the liquid is water, water with additional chemicals, or a liquid that produces foam when sprayed.
 20. A liquid spray system according to any one of claims 17, including a multi-stage pump drive.
 21. A liquid spray system according to claim 20, the multi-stage pump drive including a three stage drive hydro-motor configured to adjust pump speed in three steps.
 22. A liquid spray system according to claim 17, further including a liquid pressure relief system enabling return of liquid back to the supply reservoir.
 23. A liquid spray system according to claim 17, further including a processor, controller or vehicle information management system utilising vehicle engine speed to adjust the pump speed in operation, thereby maintaining water pressure and water pump speed within a desired range.
 24. A liquid spray system according to claim 23, the processor, controller or vehicle information management system utilising a signal relating to a vehicle speedometer signal as a factor influencing adjustment of the spray head outlet.
 25. A liquid spray system according to claim 17, the system including control means operated by an operator remote from the spray head, the control means effecting actuation of the adjuster in the spray head to adjust the outlet aperture.
 26. A liquid spray system according to claim 25, the control means provided in a cabin of a vehicle or an external control panel of the vehicle, the system being mounted to the same vehicle.
 27. A liquid spray system according to claim 26, wherein spraying is controlled by a switch or foot pedal in the vehicle. 